1. Field of the invention
The present invention relates to a low cost electronic switch for alternating current and more specifically to a touch operated switch that:
allows a multiple-way operation of a load such as a lamp or a relay by any number of same switches with only two connection leads: one towards the load and one towards an A.C. potential source, PA1 involves two distinct touch plates: one for the "turning on" and the other for the "turning off" of the switch, PA1 and need not a permanent human contact on a touch plate to remain in "on" or "off" condition. PA1 the device of Penman's U.S. Pat. No. 3,922,563 requires a permanent human contact on a touch plate for remaining in turning on condition; PA1 the device of Johnson's U.S. Pat. No. 3,549,905 besides the fact it is rather complex and hence expensive and liable to failure involves an oscillator and an antenna which are subject either to induce or to undergo interferences; PA1 the devices marketed by the French firm "Legrand" are very expensive and cannot operate a load under a minimal power (40 W to 75 W) that which is on the average just above the usual power of the electic lamps used at home and in the motel rooms (40 W to 60W); PA1 moreover, none of these electronic devices and none of the devices in conformity with Brignet'French application No. 2,344,175 or with Gehl's German application No. 2,931,880 B1 can be coupled with a device identical to itself to provide a two-way system for operating a given load. For a multiple-way operation purpose, Legrand devices can only be coupled with another type of device: a push-button switch and in this case it requires three connections and can bear only a limited number of such auxiliary devices. For the other above-cited devices which are known by their Patents or their published applications nothing in their
2. Prior Art
Prior art switches for alternating current suffer from various sorts of disadvantages. Thus, among the touch operated electronic switches:
specification or their drawings shows how these devices can be used for a multiple-way operation of a load.
For the mechanical actuated contact switches it is well known (see U.S. Pat. No. 3,922,563 already cited) that their main drawbacks are their subjection to wear and their uneasyness to be operated.
Furthermore such switches require three connections each for a two-way operation of a load and for a n-way operation of a load, two such switches require to be related through n-2 permuting device with four connections each. Such a number of connections implies multiplicity of leads, hence complexity and heaviness for electrifying a room with several issues when multiple-way operation of a lighting device is required from all the issues of the room.
For the prior art it must be told in addition that three out of the four electronic switches for which the drawings are disclosed by the Patents or applications cited here above, are based on the use of a full wave rectifying bridge of diodes with a silicon controlled rectifier and a capacitor mounted in parallel on the ouput of said bridge (see U.S. Pat. No. 3,549,905, French application No. 2,344,175, German application No. 2,931,880 B1). Said bridge input is connected by one of its pole to a load and by its other pole to an alternating current potential source. But that sort of construction did not allow up to now such a switch when coupled with an identical switch to itself to perform a two-operation of a load.